Rust inhibited soluble oil



e 3 l g t. a a, .e r a 1:. assess gg Patented Dec. 18, 1952 This invention relates to a soluble oil composition having improved corrosion and rust protection properties. More particularly, this invention relates to soluble oils incorporating minor amounts of an additive comprising an oil concentrate of an alkaline earth metal complex to improve the rust inhibiting action of the composition in the presence of large amounts of water.

Soluble oils or emulsifiable oils are used to form oilin-water type emulsions which are useful as cutting and grinding lubricants, and as processing fluids in the textile industry. The large amounts of water used in forming the emulsions cause a rust problem during contact of the fluids with metal parts, particularly the ferrous metal parts of the machinery and work pieces.

In accordance with the present invention, the improved soluble oil contains a rust inhibiting amount of a mineral lubricating oil concentrate of a complex metal containing additive. The concentrate contains from about 0.1 to weight percent of dispersed alkaline earth metal base consisting essentially of carbonate, from 1 to 40 weight percent of alkaline earth metal salt selected from the group consisting of salts of oil-soluble sulfonic acids and salt of oil-soluble olefin-phosphorus sulfide reaction products, and from about 0.5 to 30 weight percent alkaline earth metal carboxylate. At least a major portion of the carbonate compound of the metal complex is formed by the decomposition of carboxylate and the total metal content is at least 2 weight percent and less than 15 weight percent of the concentrate.

In the preferred form, the mineral oil concentrate of the metal complex containing additive of the invention comprises a refined parafiin base distillate oil having an SUS viscosity at 210 F. of from to 80, from about 3 to weight percent barium carboxylate, from about 1 to 8 percent by Weight of basic compounds consisting essentially of barium carbonate of which at least a major proportion was obtained by in situ decomposition of carboxylate, and from 3 to 25 weight percent of an oilsoluble barium petroleum sulfonate, the total metal content of the concentrate being from about 3 to 12 percent by weight.

The additive is incorporated in the soluble oil in amounts ranging from 0.05 to 1.5 percent by weight and preferably from 0.2 to 0.6 percent.

The rust preventing additive of this invention has been manufactured in accordance with the methods set forth in copending, co-assigned application Ser. No. 645,667, filed March 13, 1957, now abandoned; copending, coassigned application Ser. No. 747,089, filed July 7, 1958; and copending, co-assigned application Ser. No. 746,645, filed July 7, 1958. The methods of these applications are related. The method of application Ser. No. 645,667 broadly entail introducing a basic alkaline earth metal compound such as an oxide, hydroxide or carbonate of barium, calcium or strontium into a mineral oil, adding the dispersing agent to the oil and heating to specified temperatures while blowing with an oxidizing gas (air). The heating in this'method is done in two temperature stages, the second stage being at least 50 and preferably about 100 F. higher than the first. The second stage heating should be carried out at a temperature of at least 400 F. and preferably 450550 P. which is about the decomposition temperature of the metal carboxylates which are formed by reaction between the basic alkaline earth metal compounds and the oil oxidation products.

In the method of application Ser. No. 747,089, the metal complex containing concentrate is formed by heating a metal carboxylate in the presence of basic reacting inorganic metal compound and dispersant in a lubricating oil to a temperature between 400- and 850 F. preferably about 600 to 650 F. under non-oxidizing conditions for a period suflicient to form metal carbonate by decomposition of a substantial portion of carboxylate. In the preferred form of this method, carboxylate and detergent are first formed in situ by heating a carboxylic acid material and a dispersant precursor in the presence of the basic metal compound to form salts.

The method of application Ser. No. 746,645 differs from the last described method in that the metal carboxylate is oxidized to form the carbonate by blowing the mixture of carboxylate, detergent and basic metal compound in a lubricating oil with an oxidizing gas(air) while heating to a temperature ranging from 325 to 550 F.

Each of the above described methods are excellent for producing the additive of the invention.

Alkaline earth metal sulfonates are used in the present invention as dispersants for the metal complex in the base oil. They generally comprise normal and basic, overbased and superbased oil soluble petroleum (mahogany) sulfonates, including detergent sulfonates of barium, calcium, and strontium. Synthetic sulfonates such as alkyl aryl sulfonates from alkylated benzene or naphthalene are also effectively used. One of the best dispersing agents is an oil-soluble basic barium petroleum sulfonate made from a sulfonic acid having a molecular weight of 350-450. Alkaline earth metal salts of olefin-P 8 reaction products wherein the olefin has a molecular weight ranging from 400 to 10,000 are also excellent dispersants for this invention. A preferred dispersant of this type is the alkaline earth metal salt of polyisobutylene-P S product wherein the olefin polymer has an average molecular weight of from 700 to 900. The dispersant generally constitutes between 1 and 40 percent, but preferably from 3 to 25 weight percent, of the rust inhibiting additive of the invention.

The mineral oil component of the additive of the invention can be a parafiin base, naphthene base or mixed base oil, however a parafiin base oil is much preferred owing to the ease with which the additive is prepared when utilizing it. An example of a typical oil used in the additive of the invention is one prepared by distillation from a paraffin base crude followed by furfural refining, light acid treating, clay contacting, and solvent dewaxing. The characteristics of one particular oil refined in the above manner is as follows:

Viscosity, SUS at 210 F. 54.0 Flash point, COC, F. M... 44.0 Gravity, API 29.0 Sulfur content, wt. percent 0.4 Ash, wt. percent None Viscosity index 94 Four, F. 10

An example of the preparation of a batch of the additive is as follows:

EXAMPLE The following ingredients were charged to a ZO-barrel reaction kettle which was heated by automatically controlled electrical heating coils. The kettle was equipped with an 82.5 r.p.m. mixer having an impeller diameter of 34 inches. Baflle plates were aflixed to the bottom of the kettle just outside the tips of the impeller blades. Air was caused to enter the kettle during the reacting period through two-one inch pipes with outlets diametrically opposed about 3 inches above the impeller blade tips. Spiral water coils were installed in the kettle with necesaeeasee Ingredients: Amounts Refined paraffin base distillate oil having an SUS viscosity at 210 F. of 54 and a pour of 10 F lbs 3710 Basic barium sulfonate lbs 413 Barium oxide lbs 632 Water (distilled) lbs 74.3 Dimethyl silicone polymer conc gm 505 These ingredients were reacted in the kettle under the following reaction conditions:

Time at 350 F hours Time for 350 F. to 450 F do 1 Time at 450 F. w./air do 1.3 Time at'450 F. win/N do 2.7 Air rate s.c.f.m 132 After completion of the reaction, the product had the following characteristics:

Barium content 8.9% (wt). Viscosity, at 100 F 362 S.S.U. 1:1 kerosine blend, CO percent 1.5 (approx.).

Approximate percentages for the amount of the metal compounds of a barium complex-containing concentrate prepared as described above are as follows:

Percent wt.

Barium carbonate 8.7 Other basic barium compounds 2.3 Barium sulfonate 4.4 Barium carboxylate 7.3

The soluble oil mainly comprises a mineral lubricating oil and an emulsifying agent. The mineral oil is preferably a naphthene base distillate oil although mixed paraffin-naphthene base distillate oils are at times very effectively employed. Naphthene base distillate fractions are desirable because of their better emulsification properties and stability. In general, refined base oils having an SUS at 100 F. between' 70 and 800 are used. in the formulation of the soluble oils of this invention.

The oil-in-water emulsifying agents useful in the present invention are those known in the art. Some examples of these emulsifiers are oil soluble metal petroleum sulfonates, alkali metal naphthenates, and resinates, salts of fatty and carboxylic acids, such as guanidine salts of high molecular weight fatty acids and alkylolamine salts of oarboxylic acids containing at least carbon atoms, alkali metal salts of tall oil, etc. These soaps or salts are usually formed with sodium because of the lower cost and availability, but other alkali metal salts such as potassium and lithium salts are also used. Mixtures of emulsifiers, for example a mixture of sodium naphthenate and sodium petroleum sulfonate, a mixtur of sodium resinate, sodium naphthenate and sodium petroleum sulfonate, and a mixture of guanidine stearate and triethanolamine stearate have been found extremely useful.

The total emulsifier concentration is between 10 and percent of the total soluble oil composition with concentrations between 12 and 16 percent usually employed.

Minor amounts of coupling agents are also advantageously employed in the soluble oil composition to improve the stability thereof. Those coupling agents useful in this invention include mono and polyhydroxy alcohols, ether alcohols and phenols. Examples of these compounds include ethyl, isopropyl, n-pr opyl, isobutyl, n-butyl and n-amyl alcohols; ethyleneglycol, diethylene glycol and propylene glycol; ethylene glycol monoethyl ether (Cellosolve), ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol mono-npentyl ether, ethylene glycol mono-n-hexyl ether, diethylene glycol monoethyl ether (Carbitol), diethylene glycol monobutyl ether and cresol. The concentration of the coupling agents in the soluble oils is usually between 0.1 and 1.5 percent by Weight. A preferred coupling agent is ethylene glycol monobutyl ether at a concentration of about 0.6 percent by weight.

In preparing the soluble oil of this invention a very small amount of water is preferably used to make the soluble oil fluid and to prevent oil separation, or stratification of the emulsion, upon mixing the soluble oil with much larger amounts of water. The water content, to stabilize the oil, usually falls between 1 and 4 weight percent. A water content of about 2 percent has been found to be particularly effective in these soluble oils.

Other useful lubricant additives, to improve certain characteristics of the soluble oil, are at times used in the composition. These include, for example, bactericides, extreme pressure and oiliness agents, and settling agents.

The excellent rust preventative properties of a soluble oil emulsion containing the rust inhibiting additive of the invention was demonstrated in the rusting test which is specifically designed to evaluate the rust protection aiford ed by soluble oils and involves determination of what dilution of a soluble oil in synthetic hard water will cause the rusting of cast iron. The procedure involves placing portions of emulsions formed from the soluble oil and varying amounts of synthetic hard Water on a polished cast iron plate 11" x 5 /2 which is cross hatched into 162 equal W squares. Drops of emulsions ranging from a 10:1 dilution to a :1 dilution in increments of 5 are placed on different squares of the polished cast iron plate. The plate containing the various dilutions is allowed to stand overnight in an area where there is adequate ventilation, under which conditions the emulsion drops are evaporated in 1 to 2 hours. The squares are examined for signs of rust and the highest dilution showing no rust whatever is noted and reported as no rust and the lowest dilution showing rust is noted and reported as the rust dilution. The synthetic hard water contains 125 p.p.m.'hardness and is prepared by dissolving 2.77 g. of anhydrous calcium chloride in 5 gallons of distilled water and adjusting the pH to 6.5 to 7.5 by the addition of 10 percent of H 80 or 10 percent NaHCO The soluble oil composition used in this test consisted of about 82.8% of a naphthene base distillate oil having an SUS viscosity at F. of about 72, 4.9 percent oilsoluble sodium petroleum sulfonate, 4.5 percent sodium resinate, 4.5 percent sodium naphthenate, 1.0 percent ethylene glycol monobutyl ether, 2.0 percent water, 0.3 percent of the bactericide 2,3,4,6-tetrachlorophenol and the rust inhibiting additive of the invention having the characteristics set forth in the preceding example. The results of the rusting test are set forth in the following table:

vention permits an increase in dilution of the soluble oil' emulsion from 40:1 to a ratio of 65:1 without danger of rust. This is an increase of about 60% in dilution.

Obviously, many modifications and variations of the invention, as hereinbefore set forth, may be made without 5 departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. An improved soluble oil composition consisting essentially of a mineral lubricating oil in major proportion, about 10-20 percent by weight of an alkali metal soap emulsifier, and about 0.05-1.5 percent, sufficient to impart improved rust preventiveness to the composition, of an additive concentrate containing 2.0-15 percent by weight of alkaline earth metal, said additive concentrate being obtained from a mixture consisting essentially of a refined parafiinic lubricating oil, 140 percent by weight of a dispersant selected from the group consisting of alkaline earth metal salts of oil-soluble sulfonic acids and alkaline earth metal salts of oil-soluble olefin-phosphorus sulfide reaction products and an alkaline earth metal base, by a method comprising the step of blowing an oxygen-containing gas through the said mixture at a temperature in the range 325-650 F. until the composition contains 05-30 percent by weight of alkaline earth metal carboxylate and 0.1-15 percent by Weight of dispersed alkaline earth metal base consisting essentially of carbonate.

2. The soluble oil composition of claim 1 wherein the said additive concentrate contains 3-25 percent by weight of oil-soluble barium petroleum sulfonate, about 3-25 percent by weight of aliphatic barium carboxylate and about 1-15 percent by weight of basic barium compounds consisting essentially of barium carbonate.

3. The soluble oil composition of claim 1 wherein the said soap emulsifier is chosen from the group consisting of sodium petroleum sulfonate, sodium resinate, sodium naphthenate, and mixtures thereof.

4. The soluble oil composition of claim 1 containing 0.5-1.5 percent by weight of a coupling agent chosen from the class consisting of aliphatic alcohols, aliphatic ether alcohols and phenols.

5. The soluble oil composition of claim 1 containing about 1-4 percent of water.

6. The soluble oil composition of claim 1 diluted with water in a Water-oil ratio of from about 10:1 to about 70:1, respectively.

References Citedin the file of this patent UNITED STATES PATENTS 2,316,080 Loane et al Apr. 6, 1943 2,417,428 McLennan Mar. 18, 1947 2,655,478 Deutser ct a1 Oct. 13, 1953 2,739,124 Otto et al. Mar. 20, 1956 2,739,125 Myers et a1 Mar. 20, 1956 2,763,615 Faust Sept. 18, 1956 2,916,451 Faust Dec. 8, 1959 FOREIGN PATENTS 781,487 Great Britain Aug. 21, 1957 

1. AN IMPROVED SOLUBLE OIL COMPOSITION CONSISTING ESSENTIALLY OF A MINERAL LUBRICATING OIL IN MAJOR PROPORTION, ABOUT 10-20 PERCENT BY WEIGHT OF AN ALKALI METAL SOAP EMULSIFIER, AND ABOUT 0.05-1.5 PERCENT, SUFFICIENT TO IMPART IMPROVED RUST PREVENTIVENESS TO THE COMPOSITION, OF AN ADDITIVE CONCENTRATE CONTAINING 2.0-15 PERCENT BY WEIGHT OF ALKALINE EARTH METAL, SAID ADDITIVE CONCENTRATE BEING OBTAINED FROM A MIXTURE CONSISTING ESSENTIALLY OF A REFINED PARAFFINIC LUDRICATING OIL, 1-40 PERCENT BY WEIGHT OF A DISPERSANT SELECTED FROM THE GROUP CONSISTING OF ALKALINE EARTH METAL SALTS OF OIL-SOLUBLE OLEFIN-PHOSPHORUS SULFIDE REACTION PRODUCTS AND AN ALKALINE EARTH METAL BASE, BY A METHOD COMPRISING THE STEP OF BLOWING AN OXYGEN-CONTAINING GAS THROUGH THE SAID MIXTURE AT A TEMPERATURE IN THE RANGE 325-550*F. UNTIL THE COMPOSITION CONTAINS 0.5-30 PERCENT BY WEIGHT OF ALKALINE EARTH METAL CARBOXYLATE AND 0.1-15 PERCENT BY WEIGHT OF DISPERSED ALKALINE EARTH METAL BASE CONSISTING ESSENTIALLY OF CARBONATE. 